<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      let str = 'hello exec'

      const reg = /h(ell)o/

      //   console.log(reg.test(str))

      const res = reg.exec(str)

      //优先提取
      console.log(res)
    </script>
  </body>
</html>
